Modern mobile apps must perform well to be successful. Having an app’s fragments skip and freeze makes users feel unwelcome and degrades its usability. A stuttering game is a completely unusable app, just like a slow e-commerce app. Discover how to improve your Flutter application’s performance with our article.

Other platforms like Flutter

This cross-platform framework uses the Dart programming language. Google’s Flutter is one of the most powerful solutions on the market. How does it compare to other mobile app technologies in terms of performance?

React Native

Flutter and React Native provide smooth scrolling at 60 frames per second. On the other hand, React Native consumes more battery power and memory, and the framework is less performant.

Flutter interacts with native components directly without requiring a ‘communication bridge’, and it includes a powerful rendering engine called Skia. This technology is fairly slow and can cause a bit of a performance hit.

Ionic

For opening web pages in apps, Ionic utilizes Web View, a system component. To develop the user interface, we use typical web technologies, like HTML and CSS. We just use the mobile app to create a browser, and it displays our UI. So Ionic apps are very different from those powered by Flutter or React Native. One of the biggest issues is low performance.

Xamarin

Flutter and Xamarin are two of the most popular frameworks for creating iOS and Android apps. It is important to find out which type of Xamarin framework is used – whether it shares code between platforms, or if it contains platform-specific code that applies only to each platform.

Measuring the performance of Flutter

Profile mode performance is measured with a real device (preferably a low-end one). Since Flutter provides a wide range of options for testing and measuring performance, performance testing can be done in several ways. Listed here are a few popular methods.

  • Performance widget (The Flutter Inspector, The command line)
  • Performance view (Flutter frames chart, Timeline events chart, CPU profiler)
  • Benchmark tests via integration testing

What you can do to improve Flutter performance

  • Don’t use expensive building methods, since they consume too much CPU power.
  • Utilize const Constructor to keep widgets in a constant state and avoid excessive widget rebuilding.
  • Opacity should only be used when necessary. If there is animation, the Opacity Widget will recompile every frame, which may cause Flutter performance issues.
  • When possible, avoid calling saveLayer since it is hardware-intensive.
  • 16 milliseconds to build and render. Users won’t notice any significant difference in visual rendering if frames are rendered faster than 16ms, but it may improve battery life and reduce device heating.
  • Use The SizedBox widget. It is more efficient than the Container widget for defining a box or whitespace of specific dimensions.
  • Create child subtrees with AnimatedBuilder
  • Rather than ListView or Column, use the ListView.builder constructor if a list is not all present on a screen at once. A list’s elements are only saved in memory when they are displayed. It optimizes memory and increases performance.
  • In the case of a very large building method with hundreds of nesting levels, you may want to separate it into several methods. Even if some of the child widgets are completely static, this will force Flutter to rebuild them all every time the parent widget rebuilds. Split complicated widgets into smaller StalessWidgets to reduce CPU usage.

Conclusion

With Flutter, developers can build apps that offer native performance, even if they use visual effects heavily. We were surprised at how well Flutter handled animations and provided powerful playback controls. It is still highly recommended to follow best performance practices to avoid stuttering and errors in the application.